Simulated and modular three-dimensional tree and kit for manufacturing same

ABSTRACT

A cardboard three-dimensional tree comprises: two primary substantially triangular sheets and four secondary substantially triangular sheets, each having an apex, a base edge opposed to the apex, and two side edges connecting the apex and the base edge. A first primary sheet has a primary slot extending downwardly from the apex and a second primary sheet has a primary slot extending upwardly from the base edge and engageable in the downwardly extending primary slot defined in the first primary sheet. Each primary sheet has two secondary slots extending upwardly from the base edge. Each secondary sheet has a primary slot extending downwardly from the apex and engageable in one of the secondary slots defined in the primary sheets. The primary and the secondary sheets are engageable in an interlocking intersecting relation at the slots and cooperating to form a self-standing generally substantially triangular three-dimensional structure generally in the form of an evergreen tree.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35USC§119(e) of U.S. provisional patent application 61/363,817 filed on Jul. 13, 2010, the specification of which is hereby incorporated by reference.

TECHNICAL FIELD OF THE INVENTION

The technical field relates to three-dimensional artificial trees formed of sheet material such as cardboard and to a kit for manufacturing same.

BACKGROUND

Christmas trees are decorated evergreen coniferous trees, real or artificial and they are a tradition associated with the celebration of Christmas. There is an on-going debate between environmentalists to determine whether real or artificial trees are more environmentally friendly.

Some think that artificial trees are more environmentally friendly because they are re-used every year and thus do not generate the waste of their real counterparts. However, artificial trees are typically made with polyvinyl chloride (or PVC, otherwise known as vinyl), a non-renewable, petroleum-derived plastic.

One downside of real Christmas trees is that, because they are farmed as agricultural products, they often require repeated applications of pesticides over their typical eight-year lifecycles. Therefore, while they are growing—and then again once they are discarded—they may contribute to pollution of local watersheds. Beyond the run-off issue, the sheer number of trees that get discarded after every Christmas Holiday can be a big waste issue for municipalities that are generally not prepared to mulch them for compost.

Furthermore, both artificial and real Christmas trees must be either stored or discarded at the end of the Christmas period.

Since there is a need to reduce the impact on the environment, there is a need for a Christmas tree that is environmentally friendly, easy to assemble and disassemble, requiring a relative small storage space, and having a relatively affordable cost.

BRIEF SUMMARY OF THE INVENTION

It is therefore an aim of the present invention to address the above mentioned issues.

According to a general aspect, there is provided a cardboard three-dimensional tree comprising: at least two primary substantially triangular sheets, each one of the primary sheets having an apex, a base edge opposed to the apex, and two side edges connecting the apex and the base edge, a first one of the primary sheets having a primary slot extending downwardly from the apex and a second one of the primary sheets having a primary slot extending upwardly from the base edge, about centrally thereof, and engageable in the downwardly extending primary slot defined in the first primary sheet, each one of the primary sheets having two secondary slots extending either upwardly from the base edge or downwardly from the side edges, each one of the secondary slots being located on a respective side of the primary slot and spaced-apart thereof; and at least four secondary substantially triangular sheets, each one of the secondary substantially triangular sheets having an apex, a base edge opposed to the apex, and two side edges connecting the apex and the base edge, each one of the secondary substantially triangular sheets having a primary slot extending either downwardly from the apex or upwardly from the base edge and engageable in one of the secondary slots defined in the primary sheets, the primary and the secondary sheets positionable in interlocking intersecting relation at the slots and cooperating to form a self-standing generally substantially triangular three-dimensional structure generally in the form of a tree.

According to another general aspect, there is provided a cardboard three-dimensional tree kit comprising: at least two primary substantially triangular sheets, each one of the primary sheets having an apex, a base edge opposed to the apex, and two side edges connecting the apex and the base edge, a first one of the primary sheets having a primary slot extending downwardly from the apex and a second one of the primary sheets having a primary slot extending upwardly from the base edge, about centrally thereof, and engageable in the downwardly extending primary slot defined in the first primary sheet, each one of the primary sheets having two secondary slots extending either upwardly from the base edge or downwardly from the side edges, each one of the secondary slots being located on a respective side of the primary slot and spaced-apart thereof; and at least four secondary substantially triangular sheets, each one of the secondary substantially triangular sheets having an apex, a base edge opposed to the apex, and two side edges connecting the apex and the base edge, each one of the secondary substantially triangular sheets having a primary slot extending either downwardly from the apex or upwardly from the base edge and engageable in one of the secondary slots defined in the primary sheets.

According to still another general aspect, there is provided a three-dimensional tree comprising: at least two primary substantially triangular sheets, each one of the primary sheets having an apex, a base edge opposed to the apex, and two side edges connecting the apex and the base edge, a first one of the primary sheets having a primary slot extending downwardly from the apex and a second one of the primary sheets having a primary slot extending upwardly from the base edge, about centrally thereof, and engageable with the downwardly extending primary slot defined in the first one of the primary sheets, each one of the primary sheets having two secondary slots, each one of the secondary slots being located on a respective side of the primary slot and spaced-apart thereof; and at least four secondary substantially triangular sheets, each one of the secondary substantially triangular sheets having an apex, a base edge opposed to the apex, and two side edges connecting the apex and the base edge, each one of the secondary substantially triangular sheets having a primary slot, the secondary slots of the primary sheets extending one of upwardly from the base edge and downwardly from the side edges and the primary slot of the secondary sheets extending the other of upwardly from the base edge and downwardly from the apex and being engageable with one of the secondary slots defined in the primary sheets in an interlocking intersecting relation, the primary and the secondary sheets being engageable in an interlocking intersecting relation at the slots and cooperating to form a self-standing generally pyramidal three-dimensional structure generally in the form of an evergreen tree.

According to a further general aspect, there is provided a three-dimensional tree kit comprising: at least two primary substantially triangular sheets, each one of the primary sheets having an apex, a base edge opposed to the apex, and two side edges connecting the apex and the base edge, a first one of the primary sheets having a primary slot extending downwardly from the apex and a second one of the primary sheets having a primary slot extending upwardly from the base edge, about centrally thereof, and engageable with the downwardly extending primary slot defined in the first one of the primary sheets, each one of the primary sheets having two secondary slots, each one of the secondary slots being located on a respective side of the primary slot and spaced-apart thereof; and at least four secondary substantially triangular sheets, each one of the secondary substantially triangular sheets having an apex, a base edge opposed to the apex, and two side edges connecting the apex and the base edge, each one of the secondary substantially triangular sheets having a primary slot extending one of downwardly from the apex and upwardly from the base edge, the secondary slots of the primary sheets extending the other one of upwardly from the base edge and downwardly from the side edges and being engageable with one of the primary slots defined in the secondary sheets.

According to another general aspect, there is provided a three-dimensional tree comprising: at least one primary substantially triangular sheet having an apex, a base edge opposed to the apex, two side edges connecting the apex and the base edge, and a primary surface area; and four secondary substantially triangular sheets, each one of the secondary substantially triangular sheets having an apex, a base edge opposed to the apex, two side edges connecting the apex and the base edge, and a secondary surface area, the secondary surface area being smaller than the primary surface area, the secondary substantially triangular sheets being engageable in an interlocking intersecting relation wherein two first ones of the secondary sheets are substantially parallel to one another and spaced-apart from one another and two second ones of the secondary sheets are substantially parallel to one another, spaced-apart from one another, and substantially perpendicular to the two first ones of the secondary sheets; wherein the at least one primary sheet is engageable with the two first ones of the secondary sheets in an interlocking intersecting relation with the at least one primary sheet extending outwardly past and substantially perpendicularly to the two first ones of the secondary sheets, the at least one primary sheet extending substantially parallel to the two second ones of the secondary sheets, between the two second ones of the secondary sheets and spaced-apart therefrom.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 includes FIGS. 1 a and 1 b, FIG. 1 a is a front elevation view of a first primary substantially triangular sheet in accordance with an embodiment and FIG. 1 b is a front elevation view of a second primary substantially triangular sheet in accordance with an embodiment;

FIG. 2 includes FIGS. 2 a and 2 b, FIG. 2 a is a front elevation view of a first secondary substantially triangular sheet in accordance with an embodiment and FIG. 2 b is a front elevation view of a second secondary substantially triangular sheet in accordance with an embodiment;

FIG. 3 is a front elevation view of a tertiary substantially triangular sheet in accordance with an embodiment;

FIG. 4 is a perspective view of two of the first secondary substantially triangular sheets shown in FIG. 2 a disposed in a parallel and spaced apart relationship;

FIG. 5 includes FIGS. 5 a and 5 b, FIG. 5 a is a perspective view showing one of the second secondary substantially triangular sheet shown in FIG. 2 b configured to engage one of the first secondary substantially triangular sheet shown in FIG. 2 a and FIG. 5 b is a perspective view of two of the second secondary substantially triangular sheets shown in FIG. 2 b disposed in a parallel and spaced apart relationship and interconnected to the two first secondary substantially triangular sheets shown in FIG. 4;

FIG. 6 is a perspective view showing the first primary substantially triangular sheet shown in FIG. 1 a engaging the interconnected secondary substantially triangular sheets shown in FIG. 5 b;

FIG. 7 is a perspective view showing the second primary substantially triangular sheet shown in FIG. 1 b interconnected with the secondary substantially triangular sheets and the first primary substantially triangular sheet shown in FIG. 6;

FIG. 8 is a perspective view showing the tertiary substantially triangular sheets shown in FIG. 3 engaging the interconnected primary and secondary substantially triangular sheets shown in FIG. 7 to form a simulated Christmas tree;

FIG. 9 includes FIGS. 9 a and 9 b, FIG. 9 a is a perspective view showing three interconnected rectangular flat sheets in accordance with an embodiment, and FIG. 9 b is a perspective view showing four interconnected rectangular sheets to define a support base for the simulated Christmas tree in accordance with an embodiment;

FIG. 10 is a perspective view of a carrying box with four sheet cutouts including the parts shown in FIGS. 1 to 3 in accordance with an embodiment; and

FIG. 11 is a perspective view showing the simulated Christmas tree mounted on the support base shown in FIG. 9 b and including tree decorations in accordance with an embodiment.

It will be noted that throughout the appended drawings, like features are identified by like reference numerals.

DETAILED DESCRIPTION

Referring now to the drawings, the various parts for simulating the appearance of simulated and modular three-dimensional (3D) trees and, more particularly, of evergreen trees such as fir trees used in connection with the observance of Christmas will be described. These trees are full bodied with short trunks and are of substantially pyramidal shape. The artificial tree illustrated in the drawings for simulating this appearance includes a plurality of flat sheets of various sizes. The flat sheets are mounted in an interlocking intersecting relationship to define the simulated and modular 3D tree, as it will be described in more details below.

In the embodiment shown, the simulated and modular 3D tree 20 includes three sizes of substantially triangular flat sheets. The flat sheets include several slots for interconnection of the sheets together. In the embodiment shown, the flat sheets are characterized as being substantially triangular, even if the side edges are not straight, as it will be described in more details below. One skilled in the art will appreciate that, in an alternative embodiment (not shown), the tree can include more or less than three sizes of flat sheets.

FIG. 1 shows two primary sheets 22 a, 22 b defining the central and highest sheets of the simulated and modular 3D tree 20. Each sheet 22 has a peripheral outline which is substantially triangular. It includes an apex 24, a base edge 26, opposed to the apex 24, and two side edges 28 extending downwardly and connecting the apex 24 to the base edge 26. For the primary substantially triangular sheets 22, the apex 24 corresponds to the summit of the simulated and modular 3D tree 20. The side edges 28 include projections 30 forming the limb effect of an evergreen tree type silhouette. One skilled in the art will appreciate that the shape of the primary sheets 22 a, 22 b, can differ from the embodiment shown, for instance and without being limitative, the side edges 28 can be free of projections 30 or the number of projections can differ from the embodiment shown.

There are two embodiments of the primary sheets 22 a, 22 b. FIG. 1 a shows a first embodiment of the primary substantially triangular sheet 22 a. The first primary substantially triangular sheet 22 a includes a primary and central slot 32 a extending downwardly from the apex 24 in a direction substantially perpendicular to the base edge 26. The primary slot 32 a is aligned with a central longitudinal axis A-A of the primary sheet 22 extending through the apex 24 and it is designed to engage with the second primary substantially triangular sheet 22 b as it will be described in more details below.

The first primary substantially triangular sheet 22 a further includes two secondary slots 34 a extending upwardly from the base edge 26, each slot 34 a being located on a respective side of the central longitudinal axis A-A and spaced-apart therefrom. The secondary slots 34 a extend substantially parallel to and spaced-apart from the central longitudinal axis A-A. In the embodiment shown, the secondary slot inner ends are spaced apart longitudinally from the primary slot inner end.

The first primary substantially triangular sheet 22 a further includes two tertiary slots 36 a extending downwardly from the side edges 28, each slot 36 a being located on a respective side of the central longitudinal axis A-A and spaced-apart therefrom. The tertiary slots 36 a extend substantially parallel to the central longitudinal axis A-A and are also spaced-apart from the secondary slots 34 a. The tertiary slots 36 a are located outwardly of the secondary slots 34 a with respect to the central longitudinal axis A-A. As the primary slot 32 a, the secondary and tertiary slots 34 a, 36 a extend in a direction substantially perpendicular to the base edge 26.

In the embodiment shown, the secondary slots 34 a are substantially equidistantly spaced apart from the primary slot 32 a and their respective tertiary slots 36 a. Furthermore, in the embodiment shown, the left side of the primary sheet 22, with respect to the central longitudinal axis, is a mirror image of the right side.

FIG. 1 b shows a second embodiment of the primary substantially triangular sheet 22 b. As the first primary substantially triangular sheet 22 a, the second primary substantially triangular sheet 22 b includes a primary and central slot 32 b, two secondary slots 34 b, and two tertiary slots 36 b. The configuration of the secondary slots 34 b and two tertiary slots 36 b of the second primary substantially triangular sheet 22 b is similar to the one of the first primary substantially triangular sheet 22 a. However, on the opposite of the first primary substantially triangular sheet 22 a, the primary and central slot 32 b extends upwardly from the base edge 26 towards the apex 24. The inner end of the primary and central slot 32 a substantially corresponds to the inner end of the primary and central slot 32 b for interconnection of the two primary sheets 22 a, 22 b, as it will be described in more details below. Thus, the primary and central slot 32 a is longer than the secondary slots 34 b.

The two primary sheets 22 a, 22 b further include two base slots 38, extending upwardly from the base edge 26, each slot 38 being located on a respective side of the central longitudinal axis A-A, between the central longitudinal axis A-A and the secondary slots 34. The base slots 38 are shorter than the primary, secondary, and tertiary slots 32, 34, 36 and are designed to engage a support base 58 (FIG. 9) of the simulated and modular 3D tree 20, as it will be described in more details below. In the embodiment shown, both base slots 38 are located at the same distance from the central longitudinal axis A-A, on a respective side thereof. It is appreciated that, in alternative embodiments, the base slots 38 can be located on other sheets, that their position can change, that the simulated and modular 3D tree 20 can be free of base slots 38, and that base slots can be provided on several sheets of different sizes.

In the embodiment shown, both secondary slots 34 are located at the same distance from the central longitudinal axis A-A, on a respective side thereof. Similarly, the tertiary slots 36 are located at the same distance from the central longitudinal axis A-A, on a respective side thereof.

The primary sheets 22 a, 22 b have substantially the same height and surface area. They are higher and have a larger surface area than the secondary and tertiary sheets 42, 44 (FIGS. 2 and 3) as it will be described in more details below.

For building a simulated and modular 3D tree 20, as shown in FIGS. 8 and 11, one sheet of each primary sheet embodiment is required.

As mentioned above, the primary slots 32 of the primary sheets 22 are designed to be interconnected together to interlock both primary sheets 22 in a substantially orthogonal orientation. The secondary slots 34 of the primary sheets 22 are designed to interconnect the primary sheets 22 with orthogonally disposed secondary sheets 42 while the tertiary slots 36 of the primary sheets 22 are designed to interconnect the primary sheets 22 with orthogonally disposed tertiary sheets 44, as it will be described in more details below.

The lengths of each one of the primary slots 32, the secondary slots 34, and the tertiary slots 36 substantially correspond to half the length of the primary sheet 22 at the position of the slot. Thus, since the primary sheet 22 is longer at the apex 24, the primary slots 32 are longer than the secondary tertiary slots 34, 36. Similarly, the secondary slots 34 are larger than the tertiary slots 36.

FIG. 2 shows two secondary substantially triangular sheets 42 a, 42 b defining the intermediate sheets of the simulated and modular 3D tree 20, i.e. the one located between the primary and the tertiary sheets 22, 44. Each sheet 42 has a peripheral outline which is substantially triangular. As the primary sheets 22, each one of the secondary sheets 42 includes an apex 24, a base edge 26, opposed to the apex 24, two side edges 28 extending downwardly and connecting the apex 24 to the base edge 26, and a plurality of projections 30 extending from the side edges 28. As for the primary sheets 22, one skilled in the art will appreciate that the shape of the secondary sheet 42 can differ from the embodiment shown.

As for the primary sheets 22, there are two embodiments of the secondary sheets 42 a, 42 b. FIG. 2 a shows a first embodiment of the secondary substantially triangular sheet 42 a. The first secondary substantially triangular sheet 42 a includes a primary and central slot 46 a extending downwardly from the apex 24 in a direction substantially perpendicular to the base edge 26. The upper central slot 46 a is aligned with the central longitudinal axis A-A of the substantially triangular sheet 42 and is designed to interconnect with one of the primary substantially triangular sheets 22 as it will be described in more details below.

The first secondary substantially triangular sheet 42 a further includes two secondary slots 48 a, each extending downwardly from a respective one of the side edges 28, each slot 48 a being located on a respective side of the central longitudinal axis A-A and spaced-apart therefrom. The secondary slots 48 a extend substantially parallel to the central longitudinal axis A-A.

The first secondary substantially triangular sheet 42 a further includes two tertiary slots 50 a, each extending downwardly from a respective one of the side edges 28, each slot 50 a being located on a respective side of the central longitudinal axis A-A and spaced-apart therefrom. The tertiary slots 50 a extend substantially parallel to the central longitudinal axis A-A and are spaced-apart from the secondary slots 48 a. The tertiary slots 50 a are located outwardly of the secondary slots 48 a. As the primary slot 46 a, the secondary and tertiary slots 48 a, 50 a extend downwardly in a direction substantially perpendicular to the base edge 26.

FIG. 2 b shows a second embodiment of the secondary substantially triangular sheet 42 b. As the first secondary substantially triangular sheet 42 a, the second secondary substantially triangular sheet 42 b includes a primary and central slot 46 b, two secondary slots 48 b, and two tertiary slots 50 b. The configuration of the primary slot 46 b and the two tertiary slots 50 b of the second secondary substantially triangular sheet 42 b is similar to the one of the first secondary substantially triangular sheet 42 a. However, on the opposite of the first secondary substantially triangular sheet 42 a, the secondary slots 48 b extend upwardly from the base edge 26 towards the apex 24. The inner ends of the secondary slots 48 a substantially correspond to the inner ends of the secondary slot 48 b for interconnection of two secondary sheets 42 a, 42 b together, as it will be described in more details below.

As for the primary sheets 22, in the embodiment shown, the secondary slots 48 are substantially equidistantly spaced apart from the primary slot 46 and their respective tertiary slots 50. Furthermore, the left side of the secondary sheet 42 with respect to the central longitudinal axis A-A is a mirror image of the right side.

The lengths of each one of the primary slot 46, the secondary slots 48, and the tertiary slots 50 substantially correspond to half the length of the secondary sheet 42 at the position of the slot. Thus, since the secondary sheet 42 is longer at the central longitudinal axis A-A, the primary slots 46 are longer than the secondary and tertiary slots 48, 50. Similarly, the secondary slots 48 are longer than the tertiary slots 50.

For building a simulated and modular 3D tree 20, two sheets of each secondary sheet embodiment are required. The secondary sheets 42 are disposed in a substantially perpendicular relation with the intersecting secondary sheets 42.

In the embodiment shown, the secondary slots 48 are located at the same distance from the central longitudinal axis A-A, on a respective side thereof. Similarly, the tertiary slots 50 are located at the same distance from the central longitudinal axis A-A, on a respective side thereof.

The secondary sheets 42 a, 42 b of both embodiments have substantially the same height and surface area. They are smaller and have a smaller surface area than the primary sheets 22. However, they are higher and have a larger surface area than the tertiary sheets 44.

As mentioned above, the primary slots 46 of the secondary sheets 42 are designed to be interconnected with the orthogonally disposed primary sheets 22. The secondary slots 48 are designed to be interconnected together to interlock orthogonally disposed secondary sheets 42. The tertiary slots 50 are designed to interconnect the secondary sheets 42 with orthogonally disposed tertiary sheets 44, as it will be described in more details below.

FIG. 3 shows a tertiary sheet 44 defining one of the outer sheets of the simulated and modular 3D tree 20. Each sheet 44 has a peripheral outline which is substantially triangular. As the primary and secondary sheets 22, 42, each one of the tertiary sheet 44 includes an apex 24, a base edge 26, opposed to the apex 24, two side edges 28 extending downwardly and connected to the apex 24 to the base edge 26, and a plurality of projections 30 extending from the side edges 28. On the opposite of the primary and secondary sheets 22, 42, in the embodiment shown, there is only one embodiment of tertiary sheet 44. As for the primary and secondary sheets 22, 42, one skilled in the art will appreciate that the shape of the tertiary sheet 44 can differ from the embodiment shown.

The tertiary substantially triangular sheet 42 a includes a primary and central slot 52 extending upwardly from the base edge 26, in a direction substantially perpendicular thereto, and towards the apex 24. The primary slot 52 is aligned with the central longitudinal axis A-A of the tertiary sheet 44 and it is designed to engage with one of the primary substantially triangular sheet 22 that is orthogonally disposed as it will be described in more details below. The tertiary substantially triangular sheet 44 further includes two secondary slots 54, each extending upwardly from the base edge 26, each slot 54 being located on a respective side of the central longitudinal axis A-A and spaced-apart therefrom. The secondary slots 54 extend substantially parallel to the central longitudinal axis A-A. In the embodiment shown, both secondary slots 54 are located at the same distance from the central longitudinal axis A-A, on a respective side thereof.

The tertiary sheets 44 have substantially the same height and surface area. They are smaller and have a smaller surface area than the primary and secondary sheets 22, 42.

The lengths of each one of the primary and secondary slots 52, 54 substantially correspond to half the length of the tertiary sheet 44 at the position of the slot. Thus, the primary slot 52 is longer than the secondary slots 54.

As mentioned above, the primary slots 52 of the tertiary sheets 44 are designed to interconnect with one of the orthogonally disposed primary sheets 22. The secondary slots 54 are designed to interconnect with one of the orthogonally disposed secondary sheets 42, as it will be described in more details below.

For building a simulated and modular 3D tree 20, four tertiary sheets 44 are required. In summary, for building a simulated and modular 3D tree 20, two primary sheets 22 (one of each embodiment), four secondary sheets 42 (two of each embodiment), and four tertiary sheets 44 are required.

It is appreciated that the intersecting slots can change, i.e. the slots extending downwardly from either the side edges 28 or the apex 24 can extend upwardly from the base edge 26 and vice-versa. For instance and without being limitative, the secondary slots 34 of the primary sheets 22 can extend downwardly from the side edges 28 while the intersecting primary slots 46 of the secondary sheets 42 can extend upwardly from the base edge 26. Similarly, the tertiary slots 36 of the primary sheets 22 can extend upwardly from the base edge 26 while the intersecting primary slots 50 of the tertiary sheets 44 can extend downwardly from the apex 24. Furthermore, the tertiary slots 48 of the secondary sheets 42 can extend upwardly from the base edge 26 while the intersecting secondary slots 52 of the tertiary sheets 44 can extend downwardly from the side edges 28.

Referring now to FIGS. 4 to 8, there will be illustrated a method for assembling a simulated and modular 3D tree with the substantially triangular sheets described above. It is appreciated that the method described below is exemplary only and that variants are possible.

Turning now to FIG. 4, two first secondary sheets 42 a are first provided and disposed in a substantially parallel and spaced-apart relationship wherein the slots 46 a, 48 a, 50 a of the sheets 42 a are in register, i.e. the primary slot 46 of a first sheet 42 a is in register with the primary slot 46 of a second sheet 42 a, etc.

Then, the second secondary sheets 42 b are interconnected with the first secondary sheets 42 a in a perpendicular orientation as shown in FIG. 5. More particularly, the secondary slots 48 b of the second secondary sheets 42 b are inserted in the secondary slots 48 a of the first secondary sheets 42 a. Thus, as the first secondary sheets 42 a, the second secondary sheets 42 b are disposed in a substantially parallel and spaced-apart relationship wherein the slots 46 b, 48 b, 50 b of the sheets 42 b are in register. The first secondary sheets 42 a are perpendicular to the second secondary sheets 42 b. The inner ends of the secondary slots 48 a abut the inner ends of the secondary slots 48 b.

Then; the first primary sheet 22 a is interconnected with the two of the four secondary sheets 42. The first primary sheet 22 a can be in a perpendicular orientation with either the first or the second secondary sheets 42 a, 42 b. In the embodiment shown in FIG. 6, the first primary sheet 22 a is interconnected with the first secondary sheets 42 a, i.e. the first primary sheet 22 a is substantially perpendicular to the first secondary sheets 42 a and substantially parallel to and spaced-apart from the second secondary sheets 42 b. The secondary slots 34 a of the primary sheet 22 a are inserted in the primary slots 46 a of the secondary sheets 42 a. The inner ends of the secondary slots 34 a abut the inner ends of the primary slots 46 a. The first primary sheet 22 a extends between the two second secondary sheets 42 b and is spaced-apart therefrom.

The second primary sheet 22 b is then interconnected with the four secondary sheets 42 and the first primary sheet 22 a. The second primary sheet 22 b is in a substantially perpendicular orientation with the first primary sheet 22 a and the second secondary sheets 42 b and in a substantially parallel orientation with the first secondary sheets 42 a, as shown in FIG. 7. The primary slot 32 b of the second primary sheet 22 b is inserted in the primary slot 32 a of the first primary sheet 22 a. The inner end of the primary slot 32 a abuts the inner end of the primary slot 32 b. The secondary slots 34 b of the primary sheet 22 b are inserted in the primary slots 46 b of the secondary sheets 42 b. The inner ends of the secondary slots 34 b abut the inner ends of the primary slots 46 b. The second primary sheet 22 b extends between the two first secondary sheets 42 a and is spaced-apart therefrom.

Finally, the tertiary sheets 44 are interconnected with the primary and secondary sheets 22, 42, as shown in FIG. 8 (only three of the four tertiary sheets 44 are shown). Each one of the tertiary sheets 44 is mounted to the simulated and modular 3D tree 20 in a substantially parallel relationship to a respective one of the secondary sheets 42, spaced-apart therefrom. The primary slots 52 of the tertiary sheets 44 are inserted in a respective one of the tertiary slots 36 of the primary sheets 22. The inner ends of the primary slot 52 abut the inner ends of the tertiary slots 36. The secondary slots 54 of the tertiary sheets 44 are inserted in a respective one of the tertiary slots 50 of the secondary sheets 42. The inner ends of the secondary slots 54 abut the inner ends of the tertiary slots 50.

As shown in FIG. 8, a three-dimensional simulated and modular 3D tree 20 having a substantially pyramidal shape is built by interconnecting together a plurality of flat and substantially triangular sheets 22, 42, 44 of various sizes and designs.

Thus, the three-dimensional simulated and modular 3D tree 20 is defined by a structural system made from a criss-cross pattern of interlocking substantially triangular sheets. In an embodiment, the sheets are made of recyclable cardboard.

Each sheet is interconnected with at least two orthogonally disposed sheets of different sizes. The first primary sheet 22 a is orthogonal to and interconnected with the second primary sheet 22 b, the first secondary sheets 42 a, and two tertiary sheets 44. The second primary sheet 22 b is thus orthogonal to and interconnected with the first primary sheet 22 a, the second secondary sheets 42 b, and the other two tertiary sheets 44. Thus, the first primary sheet 22 a and the second secondary sheets 42 b extend substantially parallel to one another and in a spaced-apart relationship. Similarly, the second primary sheet 22 b and the first secondary sheets 42 a extend substantially parallel to one another and in a spaced-apart relationship. Each one of the primary sheets 22 and the secondary sheets 42 extend parallel to and in a spaced-apart relationship to two tertiary sheets. Each one of the secondary sheets 42 is orthogonal to and interconnected with two tertiary sheets 44.

In the embodiment shown, each one of the engageable slots has the same length. For instance and without being limitative, the primary slots 32 of the primary sheets 22 have the same length, the secondary slots 34 of the primary sheets 32 have the same length than the primary slots 46 of the secondary sheets 42, the tertiary slots 36 of the primary sheets 22 have the same length than the primary slots 52 of the tertiary sheets 44, the secondary slots 48 of the secondary sheets 42 have the same length, and the tertiary slots 50 of the secondary sheets 42 have the same length than the secondary slots 54 of the tertiary sheets 44.

Referring now to FIG. 9, there is shown a support base 58 to represent the trunk of the tree 20 and support the simulated 3D tree 20 on a surface. FIGS. 9 a and 9 b show a first embodiment of a support base including four substantially rectangular flat sheets 60. Each flat sheet 60 includes one short and central slot 62 extending downwardly from an upper edge 64 of the sheet 60 and two lateral slots 66, each lateral slot 66 being located on a respective side of the sheet 60. For two flat sheets 60, the lateral slots 66 extend downwardly from the upper edge 64 of the sheet 60 and for the other two flat sheets 60, the lateral slots 66 extend upwardly from a lower edge 67. They are spaced apart from one another and are designed to engage corresponding lateral slot 66 of an orthogonally disposed sheet 60 interconnectable therewith. When interconnected together, the inner ends of the lateral slots 66 abut one another. The central slots 62 are designed to engage the base slots 38 (see FIG. 1) for interconnecting and supporting the simulated 3D tree 20 as shown in FIG. 11. When the base slots 38 are inserted in the central slots 62, the simulated 3D tree 20 is mounted on its support base 58.

In the embodiment shown, for each one of the flat sheet 60, the lateral slots 66 are symmetrically provided on a respective side of the central slot 62. Furthermore, the length of the lateral slots 62 substantially corresponds to half the length of the flat sheet 60. Thus, the lateral slots 62 extending upwardly from the lower edge 67 have substantially the same length than the lateral slots 62 that extend downwardly from the upper edge 64 of the sheet 60. In the embodiment shown, the central slot 62 is shorter than the lateral slots 62.

FIG. 10 shows that the 3D tree 20 can be provided as a kit, in an unassembled form. In an embodiment, the kit can be provided in a carrying box 80 with four or more sheet cutouts 82. Each cutout 82 includes parts of the tree 20 described above. The components can be cut on a computer guided plotting machine and left in their sheet. These sheets are flat packed in the carrying box 80. A manual for assembly can also be provided in the carrying box 80. By leaving the parts in their sheet they are protected from shock damage during transport. The user assembles the tree 20 by pushing the parts from the sheets and then slides the parts together as described above. This ensures a rigid and very strong construction without the use of any glue. In an alternative embodiment, some or all of the tree parts can be already removed and separated from the sheets and placed unattached in the carrying box 80. One skilled in the art will appreciate that the number and shape of sheet cutouts can vary from the embodiment shown.

FIG. 11 shows a fully assembled 3D tree 20 mounted on the support base 58. Ornaments 74 which reproduce Christmas balls and stars are mounted to the tree sheets 22, 42, 44. The decorations 74 include a slot which is engaged with one of the sheets 22, 42, 44. It is appreciated that the 3D tree 20 can be free of ornaments 74 or that the decorations can reproduce other elements.

Thus, the entire 3D tree 20, including or excluding its support base 58, 59, is made of slotted sheets interlocked in a criss-crossing pattern, like an eggcrate style structural system.

In an embodiment, the flat sheets 22, 42, 44 are made of cellulosic fibers such as cardboard or paperboard. In an embodiment, the flat sheets 22, 42, 44 are fabricated out of conventional cardboard box type material. In an embodiment, the tree parts are made of recycled cardboard or paperboard. In an embodiment, the recycled cardboard or paperboard is substantially free of virgin fibers. The fact that the simulated and modular 3D tree 20 is made from a single material and very easy to disassemble makes it perfect for recycling.

It is appreciated that the simulated and modular 3D tree 20 can be provided in various sizes and colors. For instance and without being limitative, they can be provided in sizes ranging from a few inches to 8 feet of height. They can also be provided in a Christmas card size and used as such. Furthermore, they can be provided in Kraft paper color (brown), white, with an infinite variety of patterns. Patterns can also be printed on the surface of the sheets 22, 42, 44. For instance and without being limitative, printing can include glitter/metallic silk-screening on the ornaments or the tree itself, lamination with gloss, metallic glittering paper, and the like.

The flat sheets that are interconnected have one or several slots extending downwardly from either the apex or the side edges while the flat sheets that engage have one or several slots extending upwardly from the base edge.

In the embodiment shown and described above, the primary slots, the secondary slots, and the tertiary slots are equidistantly spaced-apart. However, one skilled in the art will appreciate that in an alternative embodiment (not shown), the distance between consecutive slots can vary. For instance and without being limitative, for the primary sheet, the distance between the secondary and the tertiary slots can be shorter than the distance between the primary and the secondary slots

It is appreciated that in an alternative embodiment, the 3D tree 20 can include two sizes of flat sheets or any higher number. For instance and without being limitative, an embodiment of the 3D tree 20 can include solely primary sheets 22 and secondary sheets 42. The number of slots varies in accordance with the number of sheets that will interconnect.

The simulated and modular 3D tree 20 is made up entirely of pre-cut sheets of cardboard which are slotted to slide together forming a central structural core forming a so-called egg crate divider type criss-crossing pattern. The 3D tree 20 described above is relatively inexpensive, eco-friendly, and lightweight. It can be made out of pre-cut sheets of cardboard and assembled without the use of special tools, fasteners, adhesives or the like. As such, the 3D tree 20 can be sold as a kit and hand assembled by merely compressively snapping the individual pieces together. Because of the use of cardboard panels in combination with an internal “egg crate divider” core, the resulting tree 20 is substantially rigid and dimensionally stable.

In a first direction, the egg crate divider structure of tree 20 involves a sequential set of five vertical sheets of cardboard, one corresponding to the primary sheet 22 of FIG. 1, two corresponding to the secondary sheets 42 of FIG. 2, and two corresponding to the tertiary sheets 44 of FIG. 3. Perpendicular to the first direction, there are five other vertical sheets of cardboard. These five sheets criss-cross with the sheets in the first direction.

The length and width of the slots are sufficient to allow the respective sheets to interlock with each other forming the egg crate divider type core structure of the tree 20, i.e. with substantially square openings.

In an alternative embodiment, the tree or the tree kit includes lights which can be mounted to the assembled tree for lightening same and to illuminate. The lights can be mounted either inwardly or outwardly of the tree structure. If the tree includes lights, the tree parts can be made of non-flammable cardboard.

The above described tree proposes an alternative to artificial or natural conventional Christmas trees, with a nice design and various finishes and colors.

The 3D tree can be stored in a box to reduce the storage space. It can be rebuilt several times.

Several alternative embodiments and examples have been described and illustrated herein. The embodiments of the invention described above are intended to be exemplary only. A person of ordinary skill in the art would appreciate the features of the individual embodiments, and the possible combinations and variations of the components. A person of ordinary skill in the art would further appreciate that any of the embodiments could be provided in any combination with the other embodiments disclosed herein. It is understood that the invention may be embodied in other specific forms without departing from the spirit or central characteristics thereof. The present examples and embodiments, therefore, are to be considered in all respects as illustrative and not restrictive, and the invention is not to be limited to the details given herein. Accordingly, while the specific embodiments have been illustrated and described, numerous modifications come to mind without significantly departing from the spirit of the invention. The scope of the invention is therefore intended to be limited solely by the scope of the appended claims. 

1. A three-dimensional tree comprising: at least two primary substantially triangular sheets, each one of the primary sheets having an apex, a base edge opposed to the apex, and two side edges connecting the apex and the base edge, a first one of the primary sheets having a primary slot extending downwardly from the apex and a second one of the primary sheets having a primary slot extending upwardly from the base edge; about centrally thereof, and engageable with the downwardly extending primary slot defined in the first one of the primary sheets, each one of the primary sheets having two secondary slots, each one of the secondary slots being located on a respective side of the primary slot and spaced-apart thereof; and at least four secondary substantially triangular sheets, each one of the secondary substantially triangular sheets having an apex, a base edge opposed to the apex, and two side edges connecting the apex and the base edge, each one of the secondary substantially triangular sheets having a primary slot, the secondary slots of the primary sheets extending one of upwardly from the base edge and downwardly from the side edges and the primary slot of the secondary sheets extending the other of upwardly from the base edge and downwardly from the apex and being engageable with one of the secondary slots defined in the primary sheets in an interlocking intersecting relation, the primary and the secondary sheets being engageable in an interlocking intersecting relation at the slots and cooperating to form a self-standing generally pyramidal three-dimensional structure generally in the form of an evergreen tree.
 2. A three-dimensional tree as claimed in claim 1, wherein two first ones of the secondary sheets further comprise two secondary slots extending downwardly from the side edges, each one of the secondary slots being located on a respective side and spaced-apart from the primary slot and two second ones of the secondary sheets further comprises two secondary slots extending upwardly from the base edge, each one of the secondary slots being located on a respective side of the primary slot and spaced-apart thereof, the secondary slots defined in the first ones of the secondary sheets being engageable with a respective one of the secondary slots defined in the second ones of the secondary sheets in interlocking intersecting relation, wherein the first ones of the secondary sheets intersect substantially perpendicularly the second ones of the secondary sheets and wherein the first ones of the secondary sheets extend substantially parallel to one another and are spaced-apart from one another and the secondary ones of the secondary sheets extend substantially parallel to one another and are spaced-apart from one another, and wherein the first one of the primary sheets intersects substantially perpendicularly the second one of the primary sheets.
 3. A three-dimensional tree as claimed in claim 1, further comprising at least four tertiary substantially triangular sheets, each one of the tertiary substantially triangular sheets having an apex, a base edge opposed to the apex, and two side edges connecting the apex and the base edge, each one of the tertiary substantially triangular sheets having a primary slot extending about centrally thereof, and two secondary slots, each one of the secondary slots being located on a respective side of the primary slot and spaced-apart thereof; each one of the primary sheets having two tertiary slots extending one of downwardly from the side edges and upwardly from the base edge, the primary slot of the tertiary sheets extending the other one of downwardly from the apex and upwardly from the base edge, each one of the tertiary slots of the primary sheet being located on a respective side of the primary slot and spaced-apart from the primary and secondary slots and engageable with the primary slot defined in one of the tertiary sheets, the primary and the tertiary sheets being engageable in an interlocking intersecting relation at the slots with the tertiary sheets being substantially perpendicular to their respective interlocking primary sheets; and each one of the secondary sheets having two tertiary slots extending one of downwardly from the side edges and upwardly from the base edge, the two secondary slots of the tertiary sheets extending the other one of upwardly from the base edge and downwardly from the side edges, each one of the tertiary slots of the secondary sheets being located on a respective side of the primary slot of the respective secondary sheet and spaced-apart from the primary and secondary slots and engageable with a respective one of the secondary slots defined in one of the tertiary sheets, the secondary and the tertiary sheets being engageable in an interlocking intersecting relation at the slots with the tertiary sheets being substantially perpendicular to their respective interlocking secondary sheets.
 4. A three-dimensional tree as claimed in claim 1, wherein the base edges of the sheets extend in a single plane and the sheets are positioned substantially perpendicularly to the plane defined by the base edges.
 5. A three-dimensional tree as claimed in claim 1, wherein the sheets are pre-cut to conform anatomically to an evergreen tree and the tree has a substantially pyramidal shape.
 6. A three-dimensional tree as claimed in claim 1, wherein the sheets are periodically slotted such as to structurally engage compatible periodic slots in orthogonally disposed sheets and the sheets are positioned at a substantially equal distance from each other.
 7. A three-dimensional tree as claimed in claim 1, wherein the secondary slots of the primary sheets extend upwardly from the base edge and the intersecting primary slots of the secondary sheets extend downwardly from the apex.
 8. A three-dimensional tree as claimed in claim 3, wherein the tertiary slots of the primary sheets extend downwardly from the side edges and the intersecting primary slots of the tertiary sheets extend upwardly from the base edge and wherein the tertiary slots of the secondary sheets extend downwardly from the side edges and the intersecting secondary slots of the tertiary sheets extend upwardly from the base edge.
 9. A three-dimensional tree as claimed in claim 1, wherein two engageable slots of two orthogonally disposed sheets have substantially the same length and wherein each one of the slots has a length corresponding substantially to half a length of the respective sheet at a position of the respective slot.
 10. A three-dimensional tree as claimed in claim 3, wherein the three-dimensional tree comprises two primary sheets, four secondary sheets, and four tertiary sheets.
 11. A three-dimensional tree as claimed in claim 3, wherein the secondary slots are equidistantly spaced-apart from the primary slots and the tertiary slots are equidistantly spaced-apart from the secondary slots.
 12. A three-dimensional tree as claimed in claim 1, wherein the sheets are made of cardboard.
 13. A three-dimensional tree as claimed in claim 1, further comprising a support base for supporting the three-dimensional tree on a surface, the support base including four substantially flat sheets engageable with one another wherein orthogonally disposed sheets are interlockable with one another.
 14. A three-dimensional tree kit comprising: at least two primary substantially triangular sheets, each one of the primary sheets having an apex, a base edge opposed to the apex, and two side edges connecting the apex and the base edge, a first one of the primary sheets having a primary slot extending downwardly from the apex and a second one of the primary sheets having a primary slot extending upwardly from the base edge, about centrally thereof, and engageable with the downwardly extending primary slot defined in the first one of the primary sheets, each one of the primary sheets having two secondary slots, each one of the secondary slots being located on a respective side of the primary slot and spaced-apart thereof; and at least four secondary substantially triangular sheets, each one of the secondary substantially triangular sheets having an apex, a base edge opposed to the apex, and two side edges connecting the apex and the base edge, each one of the secondary substantially triangular sheets having a primary slot extending one of downwardly from the apex and upwardly from the base edge, the secondary slots of the primary sheets extending the other one of upwardly from the base edge and downwardly from the side edges and being engageable with one of the primary slots defined in the secondary sheets.
 15. A three-dimensional tree kit as claimed in claim 14, wherein two first ones of the secondary sheets further comprise two secondary slots extending downwardly from the side edges, each one of the secondary slots being located on a respective one of the side edges and spaced-apart from the primary slot and two second ones of the secondary sheets further comprise two secondary slots extending upwardly from the base edge, each one of the secondary slots being located on a respective side of the primary slot and spaced-apart thereof.
 16. A three-dimensional tree kit as claimed in claim 14, further comprising at least four tertiary substantially triangular sheets, each one of the tertiary substantially triangular sheets having an apex, a base edge opposed to the apex, and two side edges connecting the apex and the base edge, each one of the tertiary substantially triangular sheets having a primary slot extending one of downwardly from the apex and upwardly from the base edge, about centrally thereof, and two secondary slots extending one of upwardly from the base edge and downwardly from the side edges, each one of the secondary slots being located on a respective side of the primary slot and spaced-apart thereof; each one of the primary sheets and secondary sheets having two tertiary slots extending one of downwardly from the side edges and upwardly from the base edge, each one of the tertiary slots being located on a respective side of the primary slot of the respective primary sheet and secondary sheet and spaced-apart from the primary and secondary slots.
 17. A three-dimensional tree kit as claimed in claim 14, wherein the sheets are pre-cut to conform anatomically to an evergreen tree, the sheets are periodically slotted such as to structurally engage compatible periodic slots in orthogonally disposed sheets and the slots are positioned at a substantially equal distance from consecutive and adjacent slots.
 18. A three-dimensional tree kit as claimed in claim 14, wherein the secondary slots of the primary sheets extend upwardly from the base edge and the intersecting primary slots of the secondary sheets extend downwardly from the apex.
 19. A three-dimensional tree kit as claimed in claim 16, wherein the tertiary slots of the primary sheets extend downwardly from the side edges and the intersecting primary slots of the tertiary sheets extend upwardly from the base edge and the tertiary slots of the secondary sheets extend downwardly from the side edges and the intersecting secondary slots of the tertiary sheets extend upwardly from the base edge.
 20. A three-dimensional tree kit as claimed in claim 14, wherein the slots have a length corresponding substantially to half a length of the sheet at a position of the slot and.
 21. A three-dimensional tree kit as claimed in claim 16, wherein the three-dimensional tree comprises two primary sheets, four secondary sheets, and four tertiary sheets.
 22. A three-dimensional tree kit as claimed in claim 16, wherein the secondary slots are equidistantly spaced-apart from the primary slots and the tertiary slots are equidistantly spaced-apart from the secondary slots.
 23. A three-dimensional tree kit as claimed in claim 14, wherein the sheets are made of cardboard.
 24. A three-dimensional tree kit as claimed in claim 14, further comprising a support base for supporting the three-dimensional tree on a surface, the support base including four flat sheets, two first ones of the flat sheets having two spaced-apart slots extending upwardly from a lower edge and two second ones of the flat sheets having two spaced-apart slots extending downwardly from an upper edge.
 25. A three-dimensional tree comprising: at least one primary substantially triangular sheet having an apex, a base edge opposed to the apex, two side edges connecting the apex and the base edge, and a primary surface area; and four secondary substantially triangular sheets, each one of the secondary substantially triangular sheets having an apex, a base edge opposed to the apex, two side edges connecting the apex and the base edge, and a secondary surface area, the secondary surface area being smaller than the primary surface area, the secondary substantially triangular sheets being engageable in an interlocking intersecting relation wherein two first ones of the secondary sheets are substantially parallel to one another and spaced-apart from one another and two second ones of the secondary sheets are substantially parallel to one another, spaced-apart from one another, and substantially perpendicular to the two first ones of the secondary sheets; wherein the at least one primary sheet is engageable with the two first ones of the secondary sheets in an interlocking intersecting relation with the at least one primary sheet extending outwardly past and substantially perpendicularly to the two first ones of the secondary sheets, the at least one primary sheet extending substantially parallel to the two second ones of the secondary sheets, between the two second ones of the secondary sheets and spaced-apart therefrom.
 26. A three-dimensional tree as claimed in claim 25, comprising two primary substantially triangular sheets, a first one of the primary sheets having a primary slot extending downwardly from the apex and a second one of the primary sheets having a primary slot extending upwardly from the base edge, about centrally thereof, and engageable with the downwardly extending primary slot defined in the first one of the primary sheets wherein the first one of the primary sheets intersects substantially perpendicularly the second one of the primary sheets, each one of the primary sheets having two secondary slots, each one of the secondary slots being located on a respective side of the primary slot and spaced-apart thereof, wherein each one of the secondary substantially triangular sheets comprises a primary slot, and wherein the secondary slots of the primary sheets extend one of upwardly from the base edge and downwardly from the side edges and the primary Slot of the secondary sheets extends the other one of upwardly from the base edge and downwardly from the apex and are engageable with one of the secondary slots defined in the primary sheets in an interlocking intersecting relation.
 27. A three-dimensional tree as claimed in claim 26, wherein the two first ones of the secondary sheets further comprise two secondary slots extending downwardly from the side edges, each one of the secondary slots being located on a respective side and spaced-apart from the primary slot and the two second ones of the secondary sheets further comprises two secondary slots extending upwardly from the base edge, each one of the secondary slots being located on a respective side of the primary slot and spaced-apart thereof, the secondary slots defined in the first ones of the secondary sheets being engageable with a respective one of the secondary slots defined in the second ones of the secondary sheets in interlocking intersecting relation.
 28. A three-dimensional tree as claimed in claim 27, further comprising four tertiary substantially triangular sheets, each one of the tertiary substantially triangular sheets having an apex, a base edge opposed to the apex, and two side edges connecting the apex and the base edge, each one of the tertiary substantially triangular sheets having a primary slot extending about centrally thereof, and two secondary slots, each one of the secondary slots being located on a respective side of the primary slot and spaced-apart thereof; each one of the primary sheets having two tertiary slots extending one of downwardly from the side edges and upwardly from the base edge, the primary slot of the tertiary sheets extending the other one of downwardly from the apex and upwardly from the base edge, each one of the tertiary slots of the primary sheets being located on a respective side of the primary slot and spaced-apart from the primary and secondary slots and engageable with the primary slot defined in one of the tertiary sheets, the primary and the tertiary sheets being engageable in an interlocking intersecting relation at the slots with the tertiary sheets being substantially perpendicular to their respective interlocking primary sheets; and each one of the secondary sheets having two tertiary slots extending one of downwardly from the side edges and upwardly from the base edge, the two secondary slots of the tertiary sheets extending the other one of upwardly from the base edge and downwardly from the side edges, each one of the tertiary slots of the secondary sheets being located on a respective side of the primary slot and spaced-apart from the primary and secondary slots and engageable with a respective one of the secondary slots defined in one of the tertiary sheets, the secondary and the tertiary sheets being engageable in an interlocking intersecting relation at the slots with the tertiary sheets being substantially perpendicular to their respective interlocking secondary sheets.
 29. A three-dimensional tree as claimed in claim 25, wherein the base edges of the sheets extend in a single plane and the sheets are positioned substantially perpendicularly to the plane defined by the base edges.
 30. A three-dimensional tree as claimed in claim 25, wherein two engageable slots of two orthogonally disposed sheets have substantially the same length and each one of the slots has a length corresponding substantially to half a length of the respective sheet at a position of the respective slot.
 31. A three-dimensional tree as claimed in claim 25, wherein the sheets are made of cardboard. 